Buffing rasp and method of making same



A 14, 1945- L A. CROCKER BUFFING' HASP AND METHOD OF MAKING" SAME FiledMarch 14, 1944 HEX F m%\ Patented Aug. 14, 1945 BUFFIN G RASP AND METHODOF MAKING SAM Luther A. Crocker, Portland, Oreg.

Application March 14, 1944, Serial No. 526,460

4 Claims.

This invention relates generally to the rubber tire industry andparticularly to a buffing rasp.

The main object of this invention is to produce a tire rasp which willoutwear existing forms of rasps of the same type and materially reducethe cost of replacement.

I accomplish these objects in the manner set forth in the followingspecification as illustrated in the accompanyin drawing, in which Fig. 1is a side elevation of the rasp.

Fig. 2 is a fragmentary development of the rasp surface.

Fig. 3 is a section taken along the line 3-3 in Fig. 1.

Fig. 4 is an enlarged section showing one of the tack units before beingimproved.

Fig. 5 is a view similar to Fig. 4 showing one of the tack units in itsimproved form.

Similar numerals refer to similar parts throughout the several views.

.Referring in detail to the drawing, there is shown a common form ofbufling rasp composed of an outer metal band I through which areprojected a plurality of tacks II, and which are held in place by asplit inner band I2 which is expanded by pressure exerted against therubber bushing I3. Such rasps are now in common use, employed in cuttingdown the treads of rubber tires preparatory to retreading.

In the production of these rasps, it is the common practice to firstpierce the holes for the tacks I I in which the metal I4 forms a limitedamount of support for the tack II. Owing to the fact that the exteriorof the tack II is relatively rough and tacks of this type varyconsiderably in size and shape, and also owing to the fact that themanner of forming the holes I for the tacks I II causes the metal I4 tobe shaped somewhat irregularly and the edge I6 of the metal I4 to besomewhat torn and rough, it follows that when and also to enable it toresist lateral wear. I ac- I amount of wear on the side of the tack I I,and in complish this by chromium plating the finished rasp, that is therim ID with the tacks I I inserted, before inserting the inner band I2.

In Fig. 4 it will be seen that there are numerous voids between the tackI I and the side of the hole addition thereto, better enables the tackII to resist such wear as is directed against it. By actual test, thesechromium plated rasps have increased the operating life of the rasp atleast three-fold and after cutting three times as much area of rubber asdid an unplated rasp, the tacks in the plated rasp were still firm andonly a fraction of them were broken as compared with the unplated rasp.

While I have thus illustrated and described my invention, it is not mydesire to be limited to the I details shown herein, but it is to coverall such forms and modifications as fall fairly within the appendedclaims.

I claim:v

l. A bufiing rasp consisting of a perforated cylindrical outer band,tacks projecting outwardly through said perforated band with the headsof the tacks engaged in-the interior of the band, a coating of chromiumcovering the exterior of the tacks and filling any Voids existingbetween said tacks and the interior of the perforations and split innerband engaging the head of the tacks.

2. A bufilng rasp consisting of a revolvable metal cylinder outwardlyflared tack openings formed therein, tacks projecting outwardly throughsaid openings, said tack openings and the tack exteriors havingrelatively rough surfaces and having voids around their adjacent facesand a chromium facing for said tacks and openings filling the voidstherein.

3. A method of forming bufllng rasps consisting of progressivelyperforating a strip of metal to form flared perforations therein, theninserting tacks into said perforations with the points projectingthrough the flared end thereof, then forming the strip intoa continuouscylinder, then plating the rasp to cover the exterior of the tacks aswell as the interior of the perforations in a manner to fill the voidsexisting around said tacks and insure against the rusting thereof.

